The present invention relates generally to methods and apparatus for dispensing epoxy adhesives, and more particularly, to apparatus and methods for preventing resin and filler particle separation in epoxy adhesives during dispensing operations.
In conventional practice, two part epoxy adhesives comprising resin and filler particles are mixed and then loaded into dispensers, such a syringes, for example. After the mixed epoxy is loaded into the dispensers, it is dispensed onto a workpiece. It has been found that the resin and filler particles can separate during use.
It has been found that conductive epoxy that has been nonuniformly mixed has inadvertently been dispensed onto substrates for adhesively attaching microelectronic circuits, such as integrated circuits, for example. Separation of the epoxy resin and silver particles often results in poor electrical, thermal, and mechanical performance characteristics of these microelectronic circuit.
There is no known mechanism for mixing epoxy in-situ during the dispensing process.
It would therefore be an advantage to have an apparatus and method that prevents separation of the resin and filler particles during use. Accordingly, it is an objective of the present invention to provide for dispensing apparatus and methods for preventing resin and filler particle separation during dispensing of epoxy adhesives.